JPH10144064A - Detecting device for last recording position - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a detecting device for the last recording position which can retrieve the last recording position and can prevent possibility of double recording in an already recorded part when a magnetic tape is unloaded and loaded again. SOLUTION: This device has a tape position storage means M1 storing the last recording position being a tape position at the time of finish of recording of a magnetic tape M0, a first additional information recording means M2 recording additional information in which the last recording position stored in a tape position storage means M1 at the time of unloading a magnetic tape is set in the magnetic tape M0, and a setting means 3 detecting additional information from the magnetic tape M0 at the time of loading the magnetic tape M0 and storing the last recording position obtained from this additional information in the tape position storage means M1. Therefore, even when the magnetic tape M0 is temporarily unloaded and loaded again, the last recording position can be retrieved in the same way as before unloading the magnetic tape M1 by storing the last recording position obtained from additional information in the tape position storage means M1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a final recording position detecting device, and more particularly to a device for detecting a final recording position of a magnetic tape.

[0002]

2. Description of the Related Art Some conventional VCRs (video cassette recorders) have a rec end search function. This VCR performs recording by winding a magnetic tape 1 around a rotating drum 2 as shown in FIG. Each of the supply reel 4 and the take-up reel 6 generates eight rotation detection pulses for one rotation, and the control device 8 counts, for example, the rotation detection pulses of the take-up reel 6 during recording, and counts the count value at the end of recording ( (P value) is stored as an R value.

After that, when the tape travels by rewinding or reproducing, the controller 8 counts up or down the rotation detection pulse according to the tape traveling direction, and updates the P value. When a rec end search instruction is input by a control button or the like, the control device 1
8 controls the tape running system so that the tape running is performed in a direction in which the P value becomes the R value by comparing the P value and the R value, and the tape running is stopped when the P value becomes the R value. Enter the recording standby state.

[0004]

In the conventional rec end search function, the R value is destroyed when the tape is taken out from the VCR. For this reason, the rec end search function cannot be used even if the tape is next mounted on the VCR. Therefore, after recording to the middle of the tape, rewinding and playing back, stopping at a position different from the final recording position and taking out the tape, when trying to continue recording by reattaching this tape, There is a problem that there is a possibility that double recording is performed on the already recorded portion.

[0005] The present invention has been made in view of the above points,
It is an object of the present invention to provide a final recording position detecting device capable of searching for a final recording position when a magnetic tape is ejected and remounted, thereby preventing the possibility of double recording of a recorded portion.

[0006]

According to the first aspect of the present invention, there is provided a tape position storage means M1 for storing a final recording position which is a tape position at the end of recording of a magnetic tape M0, as shown in FIG. First additional information recording means M2 for recording, on the magnetic tape, additional information for setting the final recording position stored in the tape position storage means when the magnetic tape is ejected, and additional information from the magnetic tape when the magnetic tape is mounted Setting means M3 for detecting information and storing the final recording position obtained from the additional information in the tape position storage means; and a search for searching the magnetic tape for the final recording position stored in the tape position storage means. Means M4.

For this reason, even when the magnetic tape is once ejected and remounted, the final recording position obtained from the additional information is stored in the tape position storage means, and the final recording position is searched in the same manner as before the ejection of the magnetic tape. This can prevent double recording of the recorded portion. According to a second aspect of the present invention, in the final recording position detecting device according to the first aspect, a second additional information recording means for recording, on the magnetic tape, additional information having a valid flag set at the end of recording on the magnetic tape. The search means confirms the end of the search when detecting the additional information with the valid flag set at the time of the search.

As described above, when the last recording position of the magnetic tape is searched, the validity of the search can be confirmed by the validity flag of the additional information. According to a third aspect of the present invention, in the final recording position detecting device according to the first or second aspect, the first additional information recording means stores, on the magnetic tape, additional information with an information flag set together with the final recording position. The information is recorded, and the setting means detects the additional information with the information flag set.

For this reason, the presence or absence of the last recording position can be confirmed by the information flag when detecting the additional information when the tape is mounted. According to the fourth aspect of the present invention, in the final recording position detecting apparatus according to the third aspect, when the setting information cannot be detected by the setting unit, the tape travels until the recording of the magnetic tape is performed. There is a correction means for detecting the additional information on which the information flag is set, and storing the final recording position obtained from the additional information in the tape position storage means.

Therefore, even when no additional information is detected when the tape is mounted, if the additional information is detected during reproduction, for example, the final recording position can be set in the tape position storage means from the additional information. According to a fifth aspect of the present invention, in the final recording position detecting device according to the second aspect, when the tape position of the magnetic tape coincides with the final recording position stored in the tape position storage means, the detection is performed from the magnetic tape. Correction means for invalidating the last recording position stored in the tape position storage means when the valid flag of the additional information is not set.

For this reason, when searching for the final recording position of the magnetic tape, it is possible to confirm whether or not the final recording position is correct by using the validity flag of the additional information.

[0012]

FIG. 2 is a block diagram showing an embodiment of a digital video camera to which the present invention is applied. In the figure, light from a subject passes through an optical system 11 to an image sensor 12.
Image. The imaging device 12 is, for example, a CCD solid-state imaging device, where it is photoelectrically converted and supplied to a video camera signal processing circuit 13 as an image signal. The video camera signal processing circuit 13 performs a series of processes such as color separation, synchronization, matrix synthesis, and the like, and outputs, for example, a luminance signal Y and a color difference signal BY,
A video signal composed of RY is generated and supplied to the recording / reproduction processing circuit 14.

The audio signal converted by the microphone 15 is supplied to an audio signal processing circuit 16 and is digitized and supplied to a recording / reproducing processing circuit 14. At the same time, an analog audio signal is supplied from a terminal 25 for monitoring. Is output. The recording / reproducing processing circuit 14 digitizes each of the supplied video signal and audio signal, performs compression and addition of an error correction code, generates a subcode, forms a recording signal, and supplies the recording signal to the magnetic head 17. Record on tape 18. Further, the signal reproduced from the magnetic tape 18 by the magnetic head 17 is subjected to error correction, expansion, and the like, and
A video signal, an audio signal, and a subcode are respectively extracted by performing analog conversion.

Various operations such as recording, reproduction, fast-forward, rewind, and rec-end search are input from the operation unit 23, and the operation signals are supplied to the control unit 24. Control unit 24
Controls the imaging element 12, the video camera signal processing circuit 13, the recording / reproducing processing circuit 14, and the audio signal processing circuit 16, and controls the tape loading mechanism 21 and the tape traveling mechanism 22, respectively. Note that the recording / reproducing processing circuit 1
4 supplies the video signal to be recorded or reproduced to the electronic viewfinder 20 for display, and the audio signal processing circuit 16 outputs the audio signal to be recorded or reproduced from the terminal 25.

FIG. 3 shows the format of one track recorded on the magnetic tape 18 as viewed from the surface in contact with the head. The magnetic head 17 scans from the bottom to the top of the recording track. A signal having 525 scanning lines and a field frequency of 60 Hz records information for one frame on, for example, ten tracks. In each track, insert data, track information, audio data, video data, and subcode are recorded in the order in which the magnetic head scans. A gap in which no data is recorded is provided between these four types of data. The track information is data for recognizing the specification of the track width, and the insert data is data serving as a reference for detecting a recording portion of each of audio data, video data, and subcode.

The subcode as additional information has a pack configuration shown in FIG. One pack is composed of 5 bytes of PC0 to PC4, the first byte PC0 is a pack header for identifying the pack, and the first to fourth bytes PC1
PC4 is the pack data. 12 packs are recorded in the one-track subcode recording area shown in FIG.
A group is added for every 120 packs of a track (one frame). Then, a title time code (TTC) describing time data (hour, minute, second, frame number) of the video signal is recorded at a predetermined position of each group.

In the present invention, a maker code pack (option pack) as shown in FIG. 5A is used. In this option pack, PC0 has a predetermined code (“1111
0000 "), and PC1 is a manufacturer code. The TPD (pack number of option packs) is represented by 8 bits of PC2 and the lower 2 bits of PC3. Is P
C2 is "00000010" and the lower two bits of PC2 are "00".

Following the option pack of FIG. 5A, an option pack of the last recording position information shown in FIG. 5B is recorded. In this pack, PC0 is a predetermined code, the first bit of PC1 is a final recording position valid flag (valid flag) Va, the second bit is a final recording position information flag (information flag) In, and the next 2 bits are The tens digit of the time data frame and the remaining four bits are the first digit of the frame number. PC2 has an MSB of 1 and the next 3 bits and 4 bits are respectively set to the tens place and the first place.
When SB is 1, the next 3 bits and 4 bits are respectively in the tens place,
PC4 has the MSB of 1 and the next 3 bits, 4
Each bit is numbered tenth and first.

The final recording position valid flag Va has a value of 1 to validate that the recording position of this pack is the final recording position, and does not use the time data of PC1 to PC4 at this time. If the value is 0, it is invalidated that the recording position of this pack is the last recording position. The last recording position information flag In has a value of 1 indicating that the time data of this pack is the last recording position of the magnetic tape. However, this pack is not the last recording position, and there is no pack where Va = 1 and In = 1.

FIG. 6 shows a flowchart of a recording end process executed by the control unit 24. In the figure, in step S10, the final recording position valid flag Va of the final recording position information pack shown in FIG. 5B is set to 1 and the final recording position information flag In is set to 0. Next, the time data of the TTC recorded immediately before on the magnetic tape 18 is stored as final recording position information in a register in the control unit 24, and the register in the control unit 24 is set to "valid for final recording position storage" in step S14. Thereafter, the final recording position information pack shown in FIG. 5B and the manufacturer code pack shown in FIG.
8, and the processing is terminated. Note that the audio data and video data of this frame are invalidated. Steps S10 and S16 correspond to the second additional information recording unit, and step S12 corresponds to the tape position storage unit M1.

FIG. 7 is a flowchart of a process performed by the control unit 24 when the magnetic tape cassette is taken out as the first additional information recording means M1. In the figure, step S20
Is the last recording position valid flag V of the last recording position information pack.
a is set to 0, and the final recording position information flag In is set to 1. In the next step S22, the final recording position information stored in the register in the control unit 24 is set to the time data of the final recording position information pack, and the final recording position information pack is stored together with the maker code pack for one frame of the magnetic tape 18. Record in the subcode of Step S2
In step 4, the magnetic tape 18 is rewound by, for example, 30 frames in consideration of the amount of tape movement due to tape loading when the magnetic tape is mounted and the amount of tape travel for reproduction synchronization. To end.

FIG. 8 shows a setting means M3 executed by the control unit 24.
Of the magnetic tape cassette insertion process will be described. In the figure, in step S30, the loaded magnetic tape 18 is run to perform subcode reproduction.
In the next sub-code reproduced in step S32, it is determined whether or not the last recording position information pack in which the last recording position information flag In is 1 is detected.
Proceeding to 34, it is determined whether or not reproduction has been performed for 40 frames or more. Here, if it is less than 40 frames, step S3
If the number of frames is equal to or greater than 40, the final recording position storage is set to invalid in a register in the control unit 24 in step S36.

On the other hand, if it is determined in step S32 that the last recording position information flag In has detected the last recording position information pack of 1, the process proceeds to step S38, and the time data of this last recording position information pack is stored in the control unit 24. It is stored in a register as final recording position information. Next, in step S40, the last recording position storage is set to valid in a register in the control unit 24, and the process ends.

FIG. 9 shows search means M executed by control unit 24 when an operation signal instructing a rec end search is supplied.
4 shows a flowchart of a rec end search process as No. 4. In the figure, in step S50, it is determined whether or not the last recording position storage is set to be valid in the register. If it is valid, the process proceeds to step S52, where the last recording position information set in the register is searched for by the search target. Set to a value. Then, in step S54, a search for detecting the TTC of the subcode and comparing it with the target value is started. In step S56, the search is performed until the time data of the TTC matches the target value, and when they match, the process proceeds to step S58.

In step S58, it is determined whether or not the last recording position information pack has been detected from the reproduced sub-code. If it has been detected, in step S60, it is determined whether or not the last recording position valid flag Va of the last recording position information pack is one. Is determined. If Va = 1, a search completion display is made in step S62, and the process ends. If the last recording position information pack is not detected in step S58, or
If the final recording position valid flag Va = 0 at 60, the flow advances to step S64 to display an incomplete search end and end the processing.

On the other hand, if the storage of the last recording position is invalid in step S50, a search impossible is displayed in step S66, and the process is terminated. Steps S62, S64, S6
The control unit 24 controls the recording / reproducing processing circuit 14 to display the images on the electronic viewfinder 20. For this reason, even when the magnetic tape is once ejected and remounted, the final recording position information obtained from the subcode as the additional information is stored in the register as the tape position storage means, and the same as before the magnetic tape is ejected. The last recorded position can be searched, thereby preventing double recording of a recorded portion.

When a subcode is detected when a tape is mounted, the presence or absence of a final recording position can be confirmed by a final recording position information flag. When the last recording position of the magnetic tape is searched by the rec-end search, the validity of the search can be confirmed by the last recording position valid flag of the subcode. FIG. 10 shows a flowchart of a missing data obtaining process as a correcting means. This process is started when any tape running is performed. In the figure, step S70
After the current tape is mounted, it is determined whether or not a recording operation has been performed. If a recording operation has been performed, the process ends. If no recording operation has been performed, the last recording position storage is enabled in the register in the control unit 24 in step S72. It is determined whether or not. If the last recording position storage is valid, the process ends. If the last recording position storage is invalid, the process proceeds to step S74 to determine whether or not the last recording position information pack is detected from the reproduced subcode.

When the last recording position information pack is detected, it is determined in step S76 whether or not the last recording position information flag In is 1, and when In = 1, the control unit 2 in step S78.
4. The final recording position storage is set to valid in the register in 4,
In step S80, the time data of the final recording position information pack is set as the final recording position information of the register, and the process ends. If the last recording position information pack is not detected in steps S74 and S76, or if In ≠ 1, the processing is terminated as it is.

With this, when the tape is run by another digital video camera or digital VCR and the tape is ejected at a position other than the recording position of the final recording position information pack, or due to the operation of the standby unit at the time of tape loading,
This is effective when the last recording position information pack cannot be detected when the cassette is mounted. FIG. 11 shows a flowchart of invalid data discarding processing as correction means executed by the control unit 24. This processing is executed when the tape is running other than recording. In the figure, in a register in the control unit 24 at step S90, it is determined whether or not the last recording position storage is valid. It is determined whether or not it is the same as the final recording position information set in the register inside. If they match, the flow advances to step S94 to reproduce the subcode and detect the last recording position information pack.

Next, in step S96, it is determined whether or not the last recording position valid flag Va is 1; if Va ≠ 1, the last recording position storage in the register is invalidated in step S98, and the process is terminated. If the last recording position storage is invalid in step S90, or if the current tape position is different from the last recording position information in step S92,
If Va = 1 at 96, the process ends as it is.

As described above, when the final recording position of the magnetic tape is searched, it is possible to confirm whether or not the final recording position is correct by the final recording position valid flag of the subcode. If the final recording position is incorrect, this can be invalidated.

[0032]

As described above, the first aspect of the present invention provides
As shown in FIG. 1, a tape position storage means M1 for storing a final recording position which is a tape position at the end of recording on the magnetic tape M0, and a final recording position stored in the tape position storage means when the magnetic tape is ejected. Additional information recording means M2 for recording the additional information with
Setting means M3 for detecting additional information from the magnetic tape when the magnetic tape is mounted, and storing the final recording position obtained from the additional information in the tape position storage means, and stored in the tape position storage means. Search means M4 for searching for the last recording position on the magnetic tape.

Therefore, even when the magnetic tape is once ejected and remounted, the final recording position obtained from the additional information is stored in the tape position storage means, and the final recording position is searched in the same manner as before the ejection of the magnetic tape. This can prevent double recording of the recorded portion. According to a second aspect of the present invention, in the final recording position detecting device according to the first aspect, the second additional information recording device records the additional information for which a valid flag is set at the end of the recording of the magnetic tape on the magnetic tape. Means for retrieving, when the retrieving means detects the additional information with the valid flag set at the time of retrieval, it confirms the end of the retrieval.

As described above, when the final recording position of the magnetic tape is searched, the validity of the search can be confirmed by the validity flag of the additional information. According to a third aspect of the present invention, in the final recording position detecting device according to the first or second aspect, the first additional information recording means transmits the additional information with an information flag set together with the final recording position to the magnetic field. Record on tape,
The setting means detects additional information on which the information flag is set.

For this reason, when detecting the additional information when the tape is mounted, the presence or absence of the last recording position can be confirmed by the information flag. According to a fourth aspect of the present invention, in the final recording position detecting apparatus according to the third aspect, when the additional information cannot be detected by the setting unit, the time until the recording of the magnetic tape is performed. There is a correction means for detecting the additional information on which the information flag is set when the tape is running, and for storing the final recording position obtained from the additional information in the tape position storage means.

For this reason, even when no additional information is detected at the time of mounting the tape, if the additional information is detected at the time of reproduction, for example, the final recording position can be set in the tape position storage means from this additional information. According to a fifth aspect of the present invention, in the final recording position detecting device according to the second aspect, when the tape position of the magnetic tape coincides with the last recording position stored in the tape position storage means, And correcting means for invalidating the last recording position stored in the tape position storage means when the validity flag of the additional information detected from is not set.

Therefore, when the last recording position of the magnetic tape is searched, it is possible to confirm whether or not the last recording position is correct by using the validity flag of the additional information.

[Brief description of the drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a block diagram of a digital video camera to which the present invention is applied.

FIG. 3 is a diagram showing a recording format.

FIG. 4 is a diagram for explaining a subcode pack.

FIG. 5 is a diagram for explaining a subcode pack.

FIG. 6 is a flowchart of a process executed by a control unit.

FIG. 7 is a flowchart of a process executed by a control unit.

FIG. 8 is a flowchart of a process executed by a control unit.

FIG. 9 is a flowchart of a process executed by a control unit.

FIG. 10 is a flowchart of a process executed by a control unit.

FIG. 11 is a flowchart of a process executed by a control unit.

FIG. 12 is a diagram for explaining a conventional device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Optical system 12 Image sensor 13 Video camera signal processing circuit 14 Recording / reproducing processing circuit 15 Microphone 16 Audio signal processing circuit 17 Magnetic head 18, M0 Magnetic tape 20 Electronic viewfinder 21 Tape loading mechanism 22 Tape running mechanism 23 Operation part M1 Tape Position storage means M2 First additional information recording means M3 Setting means M4 Search means

Claims (5)

[Claims] 1. A tape position storing means for storing a final recording position which is a tape position at the end of recording of a magnetic tape, and an addition setting the final recording position stored in the tape position storing means when the magnetic tape is ejected. First additional information recording means for recording information on the magnetic tape; detecting additional information from the magnetic tape when the magnetic tape is mounted; and storing the final recording position obtained from the additional information in the tape position storage means. A final recording position detecting device comprising: setting means; and searching means for searching on the magnetic tape for a final recording position stored in the tape position storage means. 2. The final recording position detecting device according to claim 1, further comprising: a second additional information recording unit that records, on the magnetic tape, additional information for which a valid flag is set at the end of recording on the magnetic tape; A final recording position detecting device, wherein the search means confirms the end of the search when detecting the additional information with the valid flag set during the search. 3. The final recording position detecting device according to claim 1, wherein the first additional information recording unit records, on the magnetic tape, additional information in which an information flag is set together with the final recording position. A final recording position detecting device, wherein the setting means detects the additional information on which the information flag is set. 4. The final recording position detecting device according to claim 3, wherein when the setting information cannot be detected by the setting means, the information flag is set during tape running until the recording of the magnetic tape is performed. A final recording position detecting device for detecting the additional information, and storing the final recording position obtained from the additional information in the tape position storage unit. 5. The final recording position detecting device according to claim 2, wherein when the tape position of the magnetic tape coincides with the final recording position stored in the tape position storage means, the additional information detected from the magnetic tape is detected. A final recording position detection device, comprising: a correction unit that invalidates a final recording position stored in the tape position storage unit when a valid flag is not set.